Artificial limbs are in use having highly developed designs. In the case of prostheses for lower extremities including an artificial knee joint, sophisticated technologies are used, which are particularly relevant for safety aspects of the patient. For example, the “walk” and “stand” functions permit safe standing on the one hand and on the other hand permit a motion which is adapted as closely as possible to the natural gait. For this purpose, it is necessary to make it possible for the lower leg to advance completely. Yet, in the process, it is necessary to avoid a heavy impact of the lower leg part on a stopper that limits the extension movement, while considering the patient's usual release force, for example moving the thigh stump. In this case, if applicable, progressive dampers are used which, however, only guarantee the desired function if their damping dosage is correctly set for the respective patient. The same is true for starting the gait cycle from standing and for the transition from walking to safe standing.
The control of the function of such a prosthesis by means of sensors is already known. These sensors determine the transition from one phase of the gait cycle to another phase, or the transition from the gait cycle to a standing movement and vice versa, by means of measured forces, accelerations, torques or the like. These sensors also carry out adjustments of the prosthesis for the next functional phase. An example of such a prosthesis is the leg prosthesis developed and distributed by the Applicant under the name of “C-Leg”. However, even such a highly developed prosthesis requires adjustment procedures in order to optimize the adaptation of the prosthesis function to the respective patient. Such adjustments can be undertaken taking into consideration any subjective impressions the patient has when using the prosthesis. In this context, however, it is disadvantageous that the subjective impressions of the patient change and that quantifying the impressions is hardly possible. Hence, optimizing the setting of the prosthesis must be carried out according to the trial-and-error principle, in order to approach an optimized setting.
Apparatuses are known that permit objective standing and gait analysis of the patient fitted with the prosthesis. Complex and thus expensive measuring systems are required for this purpose, which can only be maintained in a few laboratories, for example rehabilitation centers. For the standard fitting of a prosthesis by a prosthetist, such measuring systems are unattainable. Thus, the standard Fitting is carried out without the aid of such measuring systems, that is to say, substantially on the basis of the subjective impressions of the patient.